Department of Civil and Environmental Engineering, Virginia Polytechnic Institute and State University, Blacksburg, VA, 24061, USA.
Department of Chemical and Environmental Engineering, Yale Univeristy, New Haven, CT, 06520, USA.
Water Res. 2019 Feb 1;149:362-374. doi: 10.1016/j.watres.2018.11.015. Epub 2018 Nov 12.
Forward osmosis (FO) has emerged as a potentially energy-efficient membrane treatment technology to yield high-quality reusable water from various wastewater/saline water sources. A key challenge remained to be solved for FO is reverse solute flux (RSF), which can cause issues like reduced concentration gradient and loss of draw solutes. Yet no universal parameters have been developed to compare RSF control performance among various studies, making it difficult to position us in this "battle" against RSF. In this paper, we have conducted a concise review of existing RSF reduction approaches, including operational strategies (e.g., pressure-, electrolysis-, and ultrasound-assisted osmosis) and advanced membrane development (e.g., new membrane fabrication and existing membrane modification). We have also analyzed the literature data to reveal the current status of RSF reduction. A new parameter, mitigation ratio (MR), was proposed and used together with specific RSF (SRSF) to evaluate RSF reduction performance. Potential research directions have been discussed to help with future RSF control. This review intends to shed more light on how to effectively tackle solute leakage towards a more cost-effective and environmental-friendly FO treatment process.
正向渗透(FO)作为一种潜在的节能膜处理技术,可从各种废水/盐水水源中生产高质量的可再利用水。FO 面临的一个关键挑战是反向溶质通量(RSF),它会导致浓度梯度降低和汲取剂损失等问题。然而,目前还没有通用的参数来比较各种研究中 RSF 控制性能,因此很难在这场“对抗”RSF 的战斗中定位自己。在本文中,我们对现有的 RSF 减少方法进行了简明的回顾,包括操作策略(例如,压力、电解和超声辅助渗透)和先进的膜开发(例如,新的膜制造和现有的膜改性)。我们还分析了文献数据,以揭示 RSF 减少的现状。提出了一个新的参数,缓解比(MR),并与特定的 RSF(SRSF)一起用于评估 RSF 减少性能。讨论了潜在的研究方向,以帮助未来的 RSF 控制。本文旨在更深入地了解如何有效地解决溶质泄漏问题,以实现更具成本效益和环保的 FO 处理工艺。